Objective To explore the method and technique of using flatbed large C-arm machine for lowering the radiation doses received by the patients during the interventional (both diagnostic and therapeutic) procedures. Methods In this study, the radiation dose rates were recorded with the built-in radiation monitoring divice of the flatbed large C-arm machine. The distance between the water phantom. the bulb and the flat panel detector was changed in turn. and the exposure model employed was changed accordingly (different flatbed inclination angle and different value of field of vision). meanwhile the corresponding radiation doses were measured and recorded. The results were analyzed. Results When the distance between the water phantom and the bulb was fixed. the shorter the distance from the flat panel to the water phantom was, the smaller the radiation dose would be. In the same setting, the greater the field of vision (FOV) value was, the smaller the radiation dose would be; while the greater the flat panel tilt angle was. the larger the radiation dose would be. In the same condition of exposure model the smaller the frame number was. the smaller the radiation dose would be. When the other condition was constant the radiation dose produced by the exposure model of digital subtraction was greater than that by the other exposure models. Conclusion During the performing of interventional procedures, properly adjusting the factors that influence the radiation doses can effectively reduce the total radiation dose received by the patients. (J Intervent Radiol, 2011, 20 : 563-665)%目的 探讨采用平板大C介入诊疗时降低患者所接受辐射剂量的方法与技术.方法 采用平板大C自身所具有的辐射监测功能记录辐射剂量率.研究者依次改变水模、球管、平板探测器之间的距离,并采用不同的曝光模式,测量并记录相对应的剂量率.将平板倾斜不同角度和改变视野(FOV)大小,测量并记录不同曝光模式所产生的剂量率.结果 当水模与球管间距离一定时,平板离水模距离越近其辐射剂量率越小.同样条件下,FOV值越大,剂量率越小;倾斜角度越大,剂量率越大.相同曝光模式下,帧数越小,剂量率越小.其他条件相同时,数字减影的剂量率高于其他曝光模式.结论 在介入诊疗时,合理调整影响辐射剂量的因素,可有效降低患者的整体辐射水平.
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